So this is a strange one, so bare with me
Halifax consistently offer £50 cashback via your Bank Account if you "join" or "rejoin" with Sky TV.
I noticed I received this cashback last month when I have been a Sky Customer for over 5 years.
I realised, in the run up to the cashback, I was not paying by direct debit.
Then during the offer period, I set up a direct debit, which triggered the £50 cashback.
So if you have this offer currently on your bank account, you could cancel your direct debit with Sky, wait a few of months (T&C's usually stipulate 4 months with no "first" direct debit to Sky) for the offer to reappear, and once it does, set up your direct debit.
And you'll see £50 appear out of nowhere.
Worth a shot?
EDIT: Santander also offer similar cashbacks.